In the background art, there has been a proposed a technique in which a plurality of audio beams are formed by use of a speaker array constituted by a plurality of speakers disposed in a matrix, so that propagation directivities of the audio signals are controlled (for example, see Patent Document 1). By use of this technique, it is not necessary to install a plurality of speakers around a user (listener) as in a background-art surround-sound system, but it is possible to output a plurality of audio beams from one panel-like speaker array so as to reproduce a surround-sound.
FIG. 12 is a top perspective view of a room where a speaker apparatus disclosed in Patent Document 1 is installed. FIG. 12 shows an example of a speaker apparatus with a speaker array constituting a 5.1ch surround-sound system. Here, in the following description, in the 5.1ch surround-sound system, term a front left channel L(Left)ch, a front right channel R(Right)ch, a center channel C(Center)ch, a rear left channel SL(Surround Left)ch, a rear right channel SR(Surround Right)ch, and a subwoofer LFE(Low Frequency Effects)ch.
A speaker apparatus 213 shown in FIG. 12 has several hundreds of speaker units disposed in a predetermined array in one panel. The speaker apparatus 213 adjusts the timing when a surround-sound is output from each speaker unit in each channel, so as to emit the surround-sound like beams. The speaker apparatus 213 delays and controls the audio beams so that the audio beams have a focus on a desired point in the space. The sound of each channel is reflected by the ceiling or wall so as to create a sound source toward the wall. Thus, a multi-channel sound field is reproduced. As shown in FIG. 12, the speaker apparatus 213 disposed under a video apparatus 212 installed near a central portion of a room wall 220 and in front of a user U outputs sounds like a center speaker (C) and a bass compensating subwoofer (LEF) directly to the user. In addition, the speaker apparatus 213 makes walls 221 and 222 on the left and right sides of the user U reflect audio beams so as to create a virtual Rch speaker 214 and a virtual Lch speaker 215. Further, the speaker apparatus 213 makes the walls 221 and 222 on the left and right sides of the user and a wall 223 at the rear of the user U reflect audio beams so as to create a virtual SRch speaker 216 and a virtual SLch speaker 217 on the rear left and right sides of the user U. In such a manner, in the surround-sound system using a speaker array, audio signals from respective channels are delayed and controlled to be formed into beams, and these sounds formed into the beams are reflected by the walls so as to create a plurality of sound sources. Thus, a sense of surround-sound can be obtained as if a plurality of speakers were installed around the user U.
Patent Document 1: JP-T-2003-510924
When the background-art speaker array apparatus is installed, information about the listening position of the user and the width, depth and height of the room as information about the shape of the installation environment are given to the speaker array apparatus. Thus, angles of audio beams are automatically calculated so that the audio beams are set. When such a setting function is not provided in the speaker array apparatus, a specialist adjusts the angles of audio beams manually while listening to a reproduced sound from the speaker array apparatus in the listening position.
In the case of the former method, however, there is a problem that there is a limitation in the shape and installation place of the room where the speaker array apparatus is to be installed. That is, correct angles of audio beams cannot be obtained unless the room where the speaker array apparatus is installed has an ideal shape such as a rectangular parallelepiped or a cube as shown in FIG. 12, and the speaker array apparatus is installed in a position and a direction satisfying computable conditions. For that reason, audio beams of the speaker array apparatus cannot be automatically set in a room having a special shape or a room where large-sized furniture has been placed. Thus, there has been a case where the beam angles have to be adjusted manually.
On the other hand, in the case of the latter method, a major part of adjustment of audio beams depends on the subjectivity of the setup man. Accordingly, an individual difference is apt to appear in a listening environment, and knowledge and experience are required for the setting operation. For that reason, a specialist for professionally adjusting the beam angles usually carries out the adjustment of the audio beams as described above. Thus, there has been a problem that it is difficult for a user to adjust the beam angles.
It is therefore an object of the present invention to provide a speaker array apparatus in which the degree of freedom in installation place of the speaker apparatus is so high that a user can set audio beams easily, and a method for setting the audio beams of the speaker array apparatus.